Molecular evaluation of residual endodontic
microorganisms after instrumentation, irrigation and medication with either
calcium hydroxide or Septomixine.
Tang G, Samaranayake L, Yip HK
Oral Dis. 2004 Nov; 10 6: 389-97
Background and objective: The correct choice of antimicrobial agents as
inter-appointment medicaments is as important as the instrumentation and
irrigation to remove pathogens from infected root canals. Calcium hydroxide [Ca(OH)(2)]
and framycetin sulfate (Septomixine) are common endodontic medicaments.
Therefore, we evaluated the efficacy of either calcium hydroxide or
Septomixine in eliminating residual intra-canal bacteria, particularly
Actinomyces spp., during inter-appointment interval in endodontic therapy
using molecular methods. Methods: A total of 31 single-rooted teeth with
primary root canal infections were studied immediately after opening the
canals and subsequently after instrumentation, irrigation with sterile saline
and 1-week medication with either Ca(OH)(2) (n = 25) or Septomixine (n = 6).
Whole bacterial genomic DNA was isolated directly from samples and PCR with
universal primers performed to detect total intra-canal bacteria. The variable
regions of 16S rDNA of bacteria were amplified and labeled with digoxigenin
for further hybridization to detect Actinomyces spp. A total of seven
oligonucleotide probes specific for A. bovis, A. gerencseriae, A. israelii, A.
meyeri, catalase-negative A. naeslundii (genospecies 1 and 2),
catalase-positive A. naeslundii genospecies 2 and A. odontolyticus were used
to detect Actinomyces spp. in 22 of 31 medicated root canals [Ca(OH)(2): n =
17; Septomixine: n = 5]. Results: The PCR results showed that 25 of 31
examined canals were positively detected with residual microorganisms after
instrumentation, irrigation with sterile saline and 1-week medication with
either Ca(OH)(2) (n = 20) or Septomixine (n = 5). Thus, only six canals [Ca(OH)(2):
n = 5, Septomixine: n = 1] were aseptic after treatment. Hybridization results
showed higher detection frequency of both A. odontolyticus and A. gerencseriae
after treatment. Significant correlation was found between exposed pulp before
treatment and positive detection of Actinomyces spp., particularly A.
odontolyticus on the second visit (P < 0.05). Conclusion: The
conventional, 1-week medication of either Ca(OH)(2) or Septomixine in
endodontic therapy may not effectively inhibit residual bacterial growth in
all root canals during inter-appointment intervals. Further investigations
using, for instance quantitative real-time PCR analyses, are required to
substantiate the present findings.
Die Autoren untersuchen 31 Wurzelkanäle molekularbiologisch auf
die Persistenz von Keimen nach Aufbereitung, Spülen mit steriler
Kochsalzlösung und einwöchiger Einlage von Ca(OH)2 und Septomycine
(Hydrocortison + Framecytinsulfat). Dabei weisen sie persistierende Keime in 25
der 31 untersuchten Wurzelkanäle nach. Nur 6 Kanäle (5 nach Ca(OH)2- und 1
nach Septomycine-Einlage) erwiesen sich als keimfrei.